Heikki Linnakangas <heikki(at)enterprisedb(dot)com> writes:
> On further thought, there is one workload where removing the non-LRU
> part would be counterproductive:
> If you have a system with a very bursty transaction rate, it's possible
> that when it's time for a checkpoint, there hasn't been any WAL logged
> activity since last checkpoint, so we skip it. When that happens, the
> buffer cache might still be full of dirty pages, because of hint bit
> updates. That still isn't a problem on it's own, but if you then do a
> huge batch update, you have to flush those dirty pages at that point. It
> would be better to trickle flush those dirty pages during the idle period.
But wouldn't the LRU-based scan accomplish that?
regards, tom lane